Guide rails are used as a bearing and guide to support and direct the movement of a carriage, also known as a saddle, mounted to the guide rail. Such a carriage might be a component of a linear actuator, for example. In some embodiments, the carriages will include metal rollers or guide wheels that ride on raceways of the guide rail.
As technology continues to strive to reduce weight, manufacturing time and manufacturing costs (with an emphasis on material costs) while maintaining structural integrity and tolerancing, numerous guide rail configurations have been developed.
One particular configuration is the use of a base rail formed of a lighter weight, cheaper base material such as aluminum onto which harder, more wear resistant, and accurately toleranced raceways are mounted.
For example, U.S. Pat. No. 5,800,065 to Lyon teaches providing an extruded base member including a longitudinal groove on opposite sides of the base member. A carriage race is inserted into each of the grooves. The teachings and disclosure of U.S. Pat. No. 5,800,065 are hereby incorporated in its entirety by reference thereto.
U.S. Pat. No. 7,300,208 to Kuellstaedt teaches a similar guide rail that includes support ribs formed in the bottom of the grooves of the base member that are deformed during assembly of the guide rails. U.S. Pat. No. 7,300,208 emphasizes the importance of having the support ribs substantially parallel to the load transmission direction of the race. This configuration allows the support ribs to deform in a mushroom pattern with a portion of the rib deforming to both sides of the rib and permits, generally, placing the support ribs in a state of compression rather than bending. Further, these ribs extend at an angle relative to the direction in which the race is roller inserted into the grooves of the base member. The teachings and disclosure of U.S. Pat. No. 7,300,208 are hereby incorporated in its entirety by reference thereto.
Embodiments of the present invention provide improvements over the guide rails taught by U.S. Pat. No. 5,800,065, and by U.S. Pat. No. 7,300,208.